1. Field of the Invention
This invention relates to a method of fabricating multilayer laminates made of at least one non-woven layer of inorganic staple fibers and at least one non-woven layer of organic synthetic fibers, the product and use thereof.
2. Description of the Related Art
Laminates composed of bounded fabrics are useful in wall and floor coverings of constructions such as residential and commercial structures. They are particularly useful in insulation and roofing felts, where the laminates are utilized as support material. The bounded fabrics find particular applicability as carriers in bituminized roofing felts and membranes. Naturally, these laminates can be coated with other materials such as polyvinyl chloride.
Various laminates fabricated form at least a non-woven synthetic fibers and non-woven mineral materials are known in the industry. For example, EP 0 176 847 A2 discloses a laminate composed of a non-woven of man-made fibers, in particular of a polyester filament and a non-woven layer of mineral fibers. The non-woven of man-made fibers and also the non-woven of mineral fibers are pre-consolidated and then bound together by needling.
European Patent Document 0 242 524 B1 suggests adding reinforcement yarns in a lengthwise direction, wherein the non-woven material is made of mineral fibers. Example B, discloses that final consolidation of the composite as being accomplished by adding a commonly known binder in the art.
European Patent Document 0379 100 B1 discloses a laminate made of a filamentous non-woven and a glass fiber non-woven, wherein the laminate is produced by first pre-consolidating glass fiber non-wovens and then needling the non-woven with a synthetic fibers non-woven. Subsequently, final setting is completed with an aqueous solution of a polymer free melamine formaldehyde precondensate, the precondensate having a molar ratio melamine/formaldehyde of 1:1.0 to 1:3.5, wherein about 0.5 to 5% by weight of a usual hardener had been added to the solution.
Similar double-ply laminates are described in South African Document ZA 94/02763 A. Additionally, the South African document discloses, inter alia, a three-layer laminate where a non-woven of glass staple fibers is placed between two filament non-wovens of polyester prestabilized by needling whereupon the three layers are bounded together by a further needling process. The filaments of the polyester non-woven are drawn through the non-woven of glass staple fibers.
DE 195 21 838 A1 describes a compact bounded fabric which is made of at least three layers, the intermediate layer being a fabric of organic fibers provided on both sides with a reinforcement layer. Preferably, the two reinforcement layers are made of inorganic fibers. It is further suggested therein to reinforce the bounded fabric by needling and/or by conglutinating with thermal or chemical binders.
EP 0 603 633 B1 describes a flame-retarding laminate of at least one layer of a consolidated spun-laid non-woven, a scrim layer of glass fibers and a metallic foil. The laminate described therein may likewise consist of a scrim of glass fibers which lies in sandwich-like manner between two non-woven layers of polyester filaments and additionally include the prescribed metallic foil. The glass fibers of the scrim layer are threads of glass, that is to say multifilament threads of glass. The glass threads may show a twist but they may be likewise present as non-twisted filament bundles. The layers may be mechanically consolidated, (e.g., by needling) or by means of a chemical binder (e.g., polyvinyl alcohol or butadiene styrene co-polymerized). Thermoplastic adhesives, in particular in form of fibers, may likewise be utilized.
Additional multilayered laminates are described in European Patent Document EP 0 187 824 B1, which includes, inter alia, a textile fiber layer from laid organic fibers. The laminates are treated with a binder on the basis of Fluor polymer dispersions.
European Patent Document EP 0 403 403 discloses multilayered structures where non-wovens of polyester staple fibers are utilized in addition to non-wovens of glass fibers. The glass staple fibers therein need to be very precisely oriented in parallel to the surface.
European Patent Document EP 0 572 891 A1 describes laminates of non-woven and scrim which, except for the metallic foil, show a similar construction as those depicted in EP 0 603 633 B1. These laminates are likewise treated with binders.
European Patent Document EP 0 806 509 describes a support layer which, inter alia, contains a fabric and a reinforcement, wherein the reinforcement serves to neutralize forces, in particular where the elongation ranges between 0 and 1% elongation. Herein, the use of a binder is also suggested.
Some of the disadvantages associated with the laminates described above is that they require a final consolidation, with the aid of binders. The objective of this final consolidation is to improve the strength of the laminate that functions as a support for roofing felts and insulation lines, as well as the product which undergoes bituminization.
Additional drawbacks associated with the commercially available laminates include lack of mechanical strength (e.g., delamination), dimensional stability, tear propagation and flame retardant properties.
To meet the requirements of the roofing, sealing, flooring and insulating industries and to overcome the disadvantages of the related art, it is an object of the present invention to provide bounded fabrics or laminates made of at least one non-woven layer of organic synthetic fibers and a non-woven layer of inorganic staple fibers, which is produced in a quick and facile manner.
It is another object of the present invention to provide a laminate which is not subject to final consolidation through the use of a binder, and provides improved mechanical strength including tear propagation strength, peel strength and nail tear strength upon saturation, impregnation or lamination with bitumen or other synthetics.
It is a further object of the present invention to utilize the laminates as carrier webs and in particular bitumen webs.
It is yet another object of the present invention for the production of laminates which are capable of being easily saturated and impregnated with bitumen or other synthetics and thus may serve as support layers for roofing felts, sealing membranes, floor coverings and the like.
It is a further object of the present invention to provide a method for the production of a laminate which exhibits improved flexibility, dimensional stability during and after bituminization, and special flame retarding properties.
It is yet another object of the invention to provide laminates where as bituminized webs or membranes, the proportion of the synthetic non-wovens vis-a-vis the proportion of non-woven of glass fibers can be reduced without the occurrence of marked drawbacks to bounded fabric, and yet have improved fire retardant characteristics, favorable flexibility and good delamination properties. Additionally, the produced bituminized webs can be easily manipulated as roofing felts in the welding and casting processes. These webs simply do not exert a banana curving effect since they are heat shrunken.
Other objects and aspects of the invention will become apparent to one of ordinary skill in the art upon review of the specification and claims appended hereto.